US3721620A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the extraction of aromatic hydrocarbons
Assignee: SnamProgetti SpA
•
Filing: 1970-07-17
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Granted: 1973-03-20
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Expires: 1990-07-17
Abstract
Abstract A MULTI-STAGE COUNTERCURRENT PROCESS FOR THE SOLVENT EXTRACTION OF AROMATIC HYDROCARBONS FOR A MIXED FEED STOCK IS DISCLOSED WHEREIN THE FEED IS CONTACTED WITH SOLVENT AND EXTRACTED IN A FIRST STAGE, EXTRACT FROM THE FIRST STAGE IS PURIFIED IN A SECOND STAGE BY COUNTERCURRENT CONTACT WITH AN OVERHEAD FRACTION FROM A THIRD STAGE WHEREIN THE SECOND STAGE EXTRACT IS DISTILLED, AND RECTIFICATION IS EFFECTED IN A FOURTH STAGE WHEREIN WATER IS REFLUXED AND A PART OF THE WATER, OBTAINED AS REFLUX FREE OF SOLVENT, IS VAPORIZED AND RECYCLED TO THE BOTTOM OF THIS RECTIFICATION STAGE TO RECOVER THE SENSIBLE HEAT OF LEAN SOLVENT. D R A W I N G
Inventors
- 👤 G Paret
- 👤 E Cinelli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:31
CPC Classifications
C; C07; C07C; C07C7/00; C07C7/04; C07C7/05; C07C7/08; B; B01; B01D; B01D11/00; B01D11/04; B01D11/0488; C07C7/005; C07C7/10
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-19 | 1976-09-18 | 1977-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-19 | 1980-09-18 | 1981-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-19 | 1984-09-18 | 1985-03-20 | $7700.00 | Window Closed / Lapsed |